/* * This file is part of the coreboot project. * * (C) Copyright 2001 Wolfgang Denk, DENX Software Engineering, wd@denx.de. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License or (at your * option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * From U-Boot 2016.05 */ #include <console/console.h> #include <rtc.h> #define FEBRUARY 2 #define STARTOFTIME 1970 #define SECDAY 86400L #define SECYR (SECDAY * 365) #define LEAP_YEAR(year) ((year) % 4 == 0) #define DAYS_IN_YEAR(a) (LEAP_YEAR(a) ? 366 : 365) #define DAYS_IN_MONTH(a) (month_days[(a) - 1]) static const int month_offset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; static const char * const weekdays[] = { "Sun", "Mon", "Tues", "Wednes", "Thurs", "Fri", "Satur", }; static int leaps_to_year(int year) { return year / 4 - year / 100 + year / 400; } /* This only works for the Gregorian calendar after Jan 1 1971. */ static int rtc_calc_weekday(struct rtc_time *tm) { int leaps_to_date; int day; if (tm->year < 1971) return -1; day = 4; /* Jan 1 1970 was a Thursday. */ /* Number of leap corrections to apply up to end of last year */ leaps_to_date = leaps_to_year(tm->year - 1) - leaps_to_year(1970); /* * This year is a leap year if it is divisible by 4 except when it is * divisible by 100 unless it is divisible by 400 * * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 is. */ if ((tm->year % 4) && ((tm->year % 100 != 0) || (tm->year % 400 == 0)) && (tm->mon > 2)) { /* We are past Feb. 29 in a leap year */ day++; } day += (tm->year - 1970) * 365 + leaps_to_date + month_offset[tm->mon-1] + tm->mday; tm->wday = day % 7; return 0; } int rtc_to_tm(int tim, struct rtc_time *tm) { int month_days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; register int i; register long hms, day; day = tim / SECDAY; hms = tim % SECDAY; /* Hours, minutes, seconds are easy */ tm->hour = hms / 3600; tm->min = (hms % 3600) / 60; tm->sec = (hms % 3600) % 60; /* Number of years in days */ for (i = STARTOFTIME; day >= DAYS_IN_YEAR(i); i++) day -= DAYS_IN_YEAR(i); tm->year = i; /* Number of months in days left */ if (LEAP_YEAR(tm->year)) DAYS_IN_MONTH(FEBRUARY) = 29; for (i = 1; day >= DAYS_IN_MONTH(i); i++) day -= DAYS_IN_MONTH(i); DAYS_IN_MONTH(FEBRUARY) = 28; tm->mon = i; /* Days are what is left over (+1) from all that */ tm->mday = day + 1; /* Determine the day of week */ return rtc_calc_weekday(tm); } /* * Converts Gregorian date to seconds since 1970-01-01 00:00:00. * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. * * [For the Julian calendar (which was used in Russia before 1917, * Britain & colonies before 1752, anywhere else before 1582, * and is still in use by some communities) leave out the * -year / 100 + year / 400 terms, and add 10.] * * This algorithm was first published by Gauss (I think). * * WARNING: this function will overflow on 2106-02-07 06:28:16 on * machines where long is 32-bit! (However, as time_t is signed, we * will already get problems at other places on 2038-01-19 03:14:08) */ unsigned long rtc_mktime(const struct rtc_time *tm) { int mon = tm->mon; int year = tm->year; int days, hours; mon -= 2; if (0 >= (int)mon) { /* 1..12 -> 11, 12, 1..10 */ mon += 12; /* Puts Feb last since it has leap day */ year -= 1; } days = (unsigned long)(year / 4 - year / 100 + year / 400 + 367 * mon / 12 + tm->mday) + year * 365 - 719499; hours = days * 24 + tm->hour; return (hours * 60 + tm->min) * 60 + tm->sec; } void rtc_display(const struct rtc_time *tm) { printk(BIOS_INFO, "Date: %4d-%02d-%02d (%sday) Time: %2d:%02d:%02d\n", tm->year, tm->mon, tm->mday, (tm->wday < 0 || tm->wday > 6) ? "unknown " : weekdays[tm->wday], tm->hour, tm->min, tm->sec); }